This year, it will be Jackie darting around the barriers supporting Simon in his first Canberra Marathon.

After both raced a 45km event just five weeks ago, Jackie Fairweather has decided not to return and defend her Canberra Marathon title this Sunday.

But Simon will don the long-distance runners.

''I'm not really that competitive in either attitude or ability, for an average runner I go ok but I just enjoy the experience really,'' Simon Fairweather said.

''I'm looking forward to finally running in Canberra though. I've been saying for a number of years I wanted to do it so now I'm finally ready and here, so it should be good.''

In the past few years he and Jackie have built up an impressive list of distance-running achievements.

Of course, they aren't your average athletes.

Simon Fairweather won Olympic gold at Sydney in 2000 in archery while Jackie Fairweather (nee Gallagher) is a two-time world title-winning triathlete and Commonwealth games marathon bronze medallist.

''I think we have only raced two marathons together, but we have done a few longer distance events the 45km last month and the bush capital 60km,'' Jackie Fairweather said.

''It's just a different challenge and brings out other things like pacing and nutrition,'' Jackie Fairweather said.

''We both had sporting careers that reached the top level, so now it's time for different challenges and I think we are both attracted to the mental and physical challenges in long-distance running.''

Simon Fairweather said he just likes the chance to get out and about.

''What I like is that they are a bit of an adventure, particulary the longer 50 or 60km events and the Brindabella classic you are out amongst it in the bush, it's great fun,'' he said.

This weekend Simon will be aiming to set a personal best in the marathon and break 2hr50min.

''I'd like to try, whether I can remains to be seen but I did a half-marathon and ran a 4min kilometre ok ... so we'll see,'' he said.